1. Field of the Invention
The present invention relates to a flat keyboard arrangement for use in electronic equipment, such as an clectronic cash register, point of sales system, computer terminal, or the like
2. Description of the Prior Art
A flat keyboard arrangement generally includes a pressure sensitive touch panel which is equipped with an array of switches aligned in two orthogonal directions. Each switch dcfincs a key. The surface of the touch panel is usually drawn with blocks to show the boundaries of the keys. The blocks may be numbered sequentially to enable the user to distinguish the keys. Alternatively, the user may write his own sign or mark on each key. However, the marks on the keys may be scraped off after a period of use.
An improved flat keyboard arrangement is disclosed in U.S. Pat. No. 4,257,179 to Oka et al. According to this reference, the flat keyboard includes a plurality of transparent touch sensitive switches aligned in a matrix. An item list sheet is placed blow the keyboard panel in order to mark each of the touch sensitive switches. The sheet may be replaced with another sheet by the rotation of a drum at which the top end side of the sheet is connected.
According to the arrangement disclosed in U.S. Pat. No. 4,257,179, the item list sheet is placed mechanically, so that the arrangement itself is bulky. Also, it takes time to change the sheets, so that the operator must pause while the sheet is being changed. Furthermore, it is very difficult to change the marks or indications on each sheet.